ID31685841
Published Date2019-11-04
JournalScientific reports, 2019-11-04, Volume 9 Find other publications in this journal
Author Info
  • Electronics Research Laboratory, Department of Physics, University of Helsinki, Helsinki, Finland. heikki.j.nieminen@aalto.fi.
  • Electronics Research Laboratory, Department of Physics, University of Helsinki, Helsinki, Finland.
  • Department of Medicine, University of Helsinki, Helsinki, Finland.
  • Research Group of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.
  • Department of Chemistry - Radiochemistry, University of Helsinki, Helsinki, Finland.
  • Department of Rheumatology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
  • Department of Laboratory Medicine and Pathobiology, University of Toronto and Mount Sinai Hospital, Toronto, Canada.

Abstract

Localized delivery of drugs into an osteoarthritic cartilaginous lesion does not yet exist, which limits pharmaceutical management of osteoarthritis (OA). High-intensity focused ultrasound (HIFU) provides a means to actuate matter from a distance in a non-destructive way. In this study, we aimed to deliver methylene blue locally into bovine articular cartilage in vitro. HIFU-treated samples (n = 10) were immersed in a methylene blue (MB) solution during sonication (f = 2.16 MHz, peak-positive-pressure = 3.5 MPa, mechanical index = 1.8, pulse repetition frequency = 3.0 kHz, cycles per burst: 50, duty cycle: 7%). Adjacent control 1 tissue (n = 10) was first pre-treated with HIFU followed by immersion into MB; adjacent control 2 tissue (n = 10) was immersed in MB without ultrasound exposure. The MB content was higher (p < 0.05) in HIFU-treated samples all the way to a depth of 600 µm from AC surface when compared to controls. Chondrocyte viability and RNA expression levels associated with cartilage degeneration were not different in HIFU-treated samples when compared to controls (p > 0.05). To conclude, HIFU delivers molecules into articular cartilage without major short-term concerns about safety. The method is a candidate for a future approach for managing OA.